Related Experiment Video
Updated: Aug 28, 2025
10:41
Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation
Published on: January 4, 2017
13.9K
Bacterial immunity: Mobile genetic elements are hotspots for defence systems.
Anne Chevallereau1, Edze R Westra2
1Université Paris Cité, CNRS, INSERM, Institut Cochin, F-75014 Paris, France.
Current Biology : CB
|September 13, 2022
Summary
Phage-inducible chromosomal islands (PICIs) are key sites for bacterial defence systems. This research shows how competition among mobile genetic elements shapes these defences and aids understanding of their exchange in bacteria.
Area of Science:
- Microbiology
- Genetics
- Bacterial Evolution
Background:
- Mobile genetic elements (MGEs) like plasmids and bacteriophages play crucial roles in bacterial evolution.
- Bacterial defence systems are essential for survival against MGEs.
- Phage-inducible chromosomal islands (PICIs) are a class of MGEs with poorly understood roles in bacterial defence.
Purpose of the Study:
- To investigate the role of PICIs as reservoirs for bacterial defence systems.
- To understand how competition between MGEs influences the development of bacterial defence repertoires.
- To elucidate the mechanisms of defence system exchange among bacteria.
Main Methods:
- Bioinformatic analysis of bacterial genomes.
- Comparative genomics to identify defence systems associated with PICIs.
- Phylogenetic analysis to trace the evolutionary history of defence systems.
Main Results:
- PICIs are identified as significant hotspots for diverse defence systems, including those targeting phages, other PICIs, and plasmids.
- A strong correlation is observed between PICI presence and the acquisition of novel defence genes.
- Evidence suggests that PICIs actively contribute to the shaping of bacterial defence gene repertoires through competition and exchange.
Conclusions:
- PICIs are not merely parasitic elements but actively participate in bacterial defence.
- The competition between MGEs is a major driver of bacterial defence system evolution.
- Understanding PICI biology offers new insights into horizontal gene transfer and bacterial adaptation.
Related Concept Videos
01:31Defense Against Bacterial Pathogens
1.5K
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
1.5K
00:46Genomic DNA in Prokaryotes
44.4K
The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance.
Genomic Diversity in Bacteria
Although bacterial genomes are much...
Genomic Diversity in Bacteria
Although bacterial genomes are much...
44.4K
01:26Defense Mechanism Against Infection
7.2K
Natural flora, body system defenses, and inflammation are natural barriers of the body against infectious agents regardless of previous exposure. Normal floras of the human body refer to the microbial population that colonizes the skin and mucous membranes.
In addition, many body organ systems have unique defenses against infection. The skin is an intact, multilayered surface preventing invasion by microorganisms unless impaired. Mucous membranes lining the mouth, nose, and eyelids are barriers...
In addition, many body organ systems have unique defenses against infection. The skin is an intact, multilayered surface preventing invasion by microorganisms unless impaired. Mucous membranes lining the mouth, nose, and eyelids are barriers...
7.2K
01:23The Antiviral System of Bacteria and Archaea: CRISPR
105
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a adaptive immune system found in bacteria and archaea that protects against viral infections. This system enables prokaryotic cells to identify, remember, and neutralize foreign genetic elements, primarily bacteriophages, by storing fragments of the invader’s DNA as a genetic memory.The CRISPR immune response begins during an initial infection. Cas (CRISPR-associated) proteins play a central role in this...
105
02:53CRISPR and crRNAs
17.3K
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
17.3K
01:24Transposons
108
Transposons, or "jumping genes," are small mobile genetic elements (MGEs) that range from 700 to 40,000 base pairs in length. They are found in all organisms and can move within the same chromosome or transfer to different chromosomes. In some cases, transposons can also jump between different host DNA molecules, such as plasmids or viruses, contributing to genetic variability.Barbara McClintock first discovered these mobile genetic elements in the 1940s while studying maize genetics, and she...
108